Parallel reduction of a chain query in distributed databases

This paper extends the results of P.A. Bernstein and D.W. Chiu (1981), P.A. Bernstein and N. Goodman (1981), and J.D. Ullman (1988), by constructing a parallel algorithm for a subset of tree queries called chain queries. An efficient parallel algorithm for a construction of full reducers for chain queries is presented and analyzed. The authors claim that the full reduction of a chain query can be done in parallel by executing only 2n-2 semijoins in the time required for an n-1 semijoins evaluation.<
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